3 digit Armstrong Number Checker

num = int(input("Enter an integer of 3 digit : "))

sum = 0
num1 = num
while num1 > 0:
    a = num1 %10
    sum = sum + a**3
    num1 = num1 // 10

if sum == num:
    print(num, " is an armstrong number")
else:
    print(num, "is not an Armstrong number")